Method of assembly of electron tubes

ABSTRACT

A PLURALITY OF ELONGATED TUBULAR ELECTRON TUBE ELECTRODES ARE DISPOSED INTO NESTED RELATIONSHIP ON A JIG WITH BOTH THEIR LEADING AND TRAILING ENDS BEING DISPOSED RELATIVELY RAMDOMLY WITH RESPECT TO ONE ANOTHER. THE TRAILING ENDS ARE GATHERED INTO A PREDETERMINED ARRAY AND A FIRST SPACER PLATE IS MOUNTED THEREON TO FIX THE ORIENTATION OF THESE ENDS. THE ELECTRODES ARE THEN REMOVED FROM THE JIG, INVERTED, AND   MOUNTED ON A JIG WITH THE FIXED ENDS CLOSEST TO THE JIG AND THE OTHER ENDS PROJECTING THEREFROM. THE PROJECTING ENDS ARE THEN GATHERED AND A SECOND SPACER PLATE IS MOUNTED THEREON TO FIX THEIR ORIENTATION.

United States Patent Inventor Dale V. Henry Basking Ridge, NJ. 787,382

Dec. 27, 1968 June 28, 197 1 RC A Corporation Appl. No. Filed PatentedAssignee METHOD OF ASSEMBLY OF ELECTRON TUBES 2 Claims, 7 Drawing Figs.

Primary Examiner-John F. Campbell Assistant Examiner-Richard BernardLazarus Attorney-G. H. Bruestle ABSTRACT: A plurality of elongatedtubular electron tube electrodes are disposed into nested relationshipon a jig with both their leading and trailing ends being disposedrelatively randomly with respect to one another. The trailing ends aregathered into a predetermined array and a first spacer plate is mountedthereon to fix the orientation of these ends. The electrodes are thenremoved from the jig, inverted, and mounted on a jig with the fixed endsclosest to the jig and the other ends projecting therefrom. Theprojecting ends are then gathered and a second spacer plate is mountedthereon to fix their orientation.

METHOD OF ASSEMBLY OF ELECTRON TUBES BACKGROUND OFTl-IE INVENTION Thisinvention relates to the assembly of electron tubes.

In the fabrication of certain types of electron tubes, it is thepractice to mount a first electrode spacer plate on a jig, mount aplurality of elongated tubular electrodes on the jig by threading theleading ends of the electrodes through openings through the spacerplate, gather together the opposite or trailing ends of the electrodesbetween the jaws of combing tools to dispose these ends in preselectedrelation to one another, and mount a second spacer plate onto theseends.

An advantage of this method of assembly is that by threading the leadingends of the electrodes through the first spacer plate openings, asubassembly is provided in which the electrodes are, at least partially,mutually self-supporting and accurately disposed with respect to oneanother. Indeed, in some instances, the leading ends extending beyondthe spacer plate are clamped rigidly in place by suitable clampingmeans. See, for example, US. Pat. No. 2,644,998, issued July 14, I953.The purpose of fixing the leading ends is to aid in the subsequentassembly of the second spacer plate.

A problem with this prior art method is that it is difficult and tediousto thread the leading ends of the electrodes through the first spacerplate openings, especially in those instances where the electrodes arenumerous, small, and fragile, and the openings are tight fitting.Further, the threading operation often results in damage to the fragileelectrodes.

SUMMARY OF THE INVENTION A method of assembling electron tubescomprising disposing a plurality of elongated tubular electrodes intonested relationship on a jig, one set of ends of the electrodes beingengaged with a portion of the jig and the opposite set of ends of theelectrodes projecting from the jig, the various electrode ends of eachset being disposed relatively randomly with respect to one another,gathering together the projecting ends of the electrodes into apredetermined array and mounting a first spacer plate onto the gatheredends to fix the orientation of these ends, disposing the assembly ofelectrodes on a jig with the unfixed ends of the electrodes projectingtherefrom, and gathering the projecting ends of the electrodes andmounting a second spacer plate thereon.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of an electrontube cage, partly broken away, assembled in accordance with the presentinvention;

FIG. 2 is a section along line 2-2 of FIG. I;

FIG. 3 is a front elevation of an apparatus for practicing the presentinvention;

FIG. 4 is a plan view of the apparatus shown in FIG. 3;

FIG. 5 is a side elevation of the apparatus shown in FIGS. 3 and 4,parts thereof being omitted for clarity, with electrodes of the cageshown in FIGS. 1 and 2 mounted on the apparatus;

FIG. 6 is a front view of the apparatus illustrating the gathering ofthe electrodes mounted thereon, some of the electrodes being partlybroken away; and

FIG. 7 is a side view of the apparatus illustrating the remounting ofthe electrodes thereon.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION With reference toFIGS. I and 2, an electron tube cage 10 is shown. The cage 10 is for usein a ,triode electron tube, such as an RCA 684. Details of the mountingof the cage 10 on a stern, and the enclosing of the cage-stem assemblyin an envelope are well known, and are not disclosed herein.

The cage 10 comprises electrodes of known type, e.g., elongated tubularcathode 12, grid 14, and anode l6 electrodes. Opposite ends of theelectrodes extend through openings through a pair of spacer plates 18and 20, of mica, for example, which fix the relative positioning of theelectrodes.

In the assembly of the cage l0, ajig 24, and a pair of combing jaws 26and 28, as shown in FIGS. 3 and 4, are used. The jig 24 comprises ablock 30 having an upper surface 32 including an elongated V slot 34therein, and an upstanding mandrel 36. The combing jaws 26 and 28 have apair of opposed edges 38, each edge being provided with a series of Vgrooves 40 for gathering and positioning the ends of the electrodes.Means, not shown, are provided for advancing the jaws 26 and 28 towardsone another, into abutting relation, as shown in FIG. 6, and forretracting the jaws, as shown in FIG. 4. Combing jaws of the type shown,and the use of such jaws in the gathering and orienting of electrodeends, are known.

In the practice of the method of the present invention, the grid 14,cathode l2, and anode I6 electrodes are successively dropped, in theorder named, onto the mandrel 36 and around one another to provide anested assembly 45 of electrodes, as shown in FIG. 5. At this time,neither spacer plate I8 nor 20 is mounted on the assembly 45. As shown,the electrodes are maintained in vertical orientation by being disposedabout the mandrel 36 and one another. The leading ends 42, 44, and 46 ofthe cathode llZ, grid l4, and anode I6 electrodes, respectively, fitloosely within the slot 34, and are thus in relatively randomdisposition with respect to one another. The use of the slot 34, whilenot essential, is advantageous in that it provides some relativepositioning of the electrodes while not adding to the difficulty ofloading the electrodes onto the jig 24, the electrode ends beingself-centering, in one lateral dimension and the vertical dimension,within the slot 34.

Depending upon the structure of the particular electrode cage beingassembled, various other means, such as the use of other or additionalmandrels, or recesses in the jig of various configurations for receivingvarious ones of the electrode ends, can be used to receive and maintainthe electrodes in upright relation on the jig.

In the formation of the electrode assembly 45, to the point described,little efiort or skill is required on the part of the operator. Thisgreatly simplifies the assembly operation, in comparison with the priorart method, thus increasing the rate of assembly of the electrode cageswhile greatly reducing the possibility of damage to the electrodes.

Thereafter, the combing jaws 26 and 28 are advanced towards one anotherto gather into the jaw grooves 40 the trailing ends 52, 54, and 56 ofthe cathode 12, grid I4, and anode t6 electrodes, respectively,projecting from the jig to accurately position these electrode endsrelative to one another, as shown in FIG. 6. The spacer plate 18 is thenmounted on the gathered and accurately positioned electrode ends.

It is to be noted that in spite of the fact that the leading ends 42,44, and 46 of the electrodes are not held in fixed, accurate relation toone another, as in the prior art method, no difficulty is encountered ingathering the trailing electrode ends 52, 54, and 56, using standardcombing tools, or in mounting the spacer plate 18 onto the gathered endswithout damage to the electrodes.

The combing jaws 26 and 28 are retracted, and the spacer plate I8 isadvanced further along the electrode ends. The electrode assembly 45 isthen removed from the jig 24, in verted, and remounted on the jig 24with the spacer plate 18 resting on the surface 32 of the jig, and thenow fixed electrode ends 52, 54, and 56 extending into the slot 34, asshown in FIG. 7.

In the usual instance, the length of the extending ends of theelectrodes on opposite sides of the cage 10 are not equal, in which caseit is preferably to remount the assembly on a jig similar to the jig 24herein illustrated, but having a slot 34, or other recesses, of properdepth to receive the electrode ends extending beyond the spacer plateI8.

In one embodiment, not illustrated, the jig is mounted for rotationabout a horizontal axis and, upon removal of the partially completedcage assembly 45 from the jig, the jig is rotated The bottom portion ofthe jig, provided with a suitable slot, or recesses, then serves as thenew jig. Because one set of electrode ends are now fixed in place by thespacer plate 18, a mandrel is not required for the remounting of theelectrode assembly, thus speeding-up the remounting operatron.

Having remounted the electrode assembly 45 on the jig 24, the combingjaws 26 and 28 are again advanced to gather and orient the ends 42, 44,and 46 of the electrodes, whereupon the spacer plate is mounted ontothese ends to provide the completed cage 10.

lclaim:

l. A method ofassembling an electron tube comprising:

disposing a plurality of elongated tubular electrodes in nestedrelationship on a jig, one set of adjacent ends of said electrodes beingengaged with a portion of said jig and the opposite set of adjacent endsof said electrodes projecting from said portion, the various electrodeends of each set being disposed relatively randomly with respect to oneanother;

gathering together said opposite set of adjacent ends into apredetermined array while leaving the ends of said one set of adjacentends in random disposition, and mounting a spacer plate onto saidopposite set of adjacent ends to fix them in said array; thereafterdisengaging said one set of adjacent ends from said jig and disposingthe assembly of electrodes on a jig with said one set of ends projectingtherefrom; and

thereafter gathering said one set of adjacent ends into preselectedarray and mounting a spacer plate on said one set ofadjacent ends forfixing them in said array.

2. A method of assembling an electron tube as in claim 1 wherein saidstep of disposing said electrodes in nested relationship comprises:

guiding a first elongated tubular electrode onto an elongated mandrelextending upwardly from ajig and disposing the leading end of saidelectrode in loose fit within a recess in said jig; and

successively guiding further elongated tubular electrodes onto saidfirst electrode and disposing the leading ends thereof in loose fitwithin a recess in said jig.

